Perhaps the single most stunning thing about Darwin's Black Box,
Michael Behe's "Biochemical Challenge to Evolution," is the amount
of territory that its author concedes to Darwinism. As tempted as they might
be to pick up this book in their own defense, "scientific creationists"
should think twice about enlisting an ally who has concluded that the Earth
is several billion years old, that evolutionary biology has had "much
success in accounting for the patterns of life we see around us (1),"
that evolution accounts for the appearance of new organisms including antibiotic-resistant
bacteria, and who is convinced that all organisms share a "common ancestor."
In plain language, this means that Michael Behe and I share an evolutionary
view of the natural history of the Earth and the meaning of the fossil record;
namely, that present-day organisms have been produced by a process of descent
with modification from their ancient ancestors. Behe is clear, firm, and
consistent on this point. For example, when Michael and I engaged in debate
at the 1995 meeting of the American Scientific Affiliation, I argued that
the 100% match of DNA sequences in the pseudogene region of beta-globin
was proof that humans and gorillas shared a recent common ancestor. To my
surprise, Behe said that he shared that view, and had no problem with the
notion of common ancestry. Creationists who believe that Behe is on their
side should proceed with caution - he states very clearly that evolution
can produce new species, and that human beings are one of those species.

Michael Behe is Associate Professor of Biochemistry at Lehigh University,
and not surprisingly, biochemistry, his own discipline, is at the heart
of his argument. Simply stated, he claims that Darwinism, whatever it may
explain at the organismic level, fails to account for the evolution of the
complex biochemical machinery that is found in every living cell. He writes:
"for the Darwinian theory of evolution to be true, it has to account
for the molecular structure of life. It is the purpose of this book to show
that it does not." (2)

Behe engages in some rhetorical heavy-lifting to support this contention.
In the first half of his book the reader is treated to a lively description
of some of the most intricate of life's microscopic machinery - the cilia
and flagella that produce cell movement, the cascade of blood-clotting proteins,
the systems that target proteins to specific sites within the cell, the
production of antibodies by the immune system, and the intricacies of biosynthetic
pathways. Behe's descriptions of these systems are a delight to read. He
is an excellent writer, and describes the complexities of the cell with
the flair of a gifted teacher.

Why does the existence of these (and many other) systems rule out evolution?
Because they are "irreducibly complex," meaning that if they are
missing just one of their many parts, they cannot function. Behe writes
that "Irreducibly complex systems ... cannot evolve in a Darwinian
fashion." (3) Why not? Because natural selection works on small mutations
in just one component at a time. If dozens or even hundreds of distinct
proteins, precisely fashioned, are required to make a functional cilium,
how could natural selection slowly and patiently craft them, one at a time,
while waiting for the complex function of ciliary movement to emerge? It
couldn't, so, according to Behe, the hypothesis that the cilium was produced
by evolution is therefore disproved. If evolution did not make the cilium,
then "intelligent design" must have. He writes: "life on
earth at its most fundamental level, in its most critical components, is
the product of intelligent activity." (4)

If all of this has a familiar ring, it should. It is the classic "Argument
from Design," articulated so well by William Paley nearly 200 years
ago in his book Natural Theology. Behe is candid in his admiration
for Paley, and although he takes care to point out some of Paley's mistakes,
he leaves no doubt that he views the Argument from Design as his principal
logical weapon against Darwinism. To Behe, the intricacy and complexity
of natural systems at the biochemical level shows evidence of intelligent
design.

At its core, Behe's argument is about the mechanism of evolution,
which distinguishes him from "young-earth creationists" who deny
the validity of the geological ages, the appearance of new species, and
attempt to prove that the fossil record is either an illusion or a vast
conspiracy. Behe will have none of this, and explicitly denies any connection
with "creationism." (5) Nonetheless, he recognizes that his ideas
do have theological implications as well as scientific ones. He is not at
all modest about these implications, comparing the discovery of design to
achievements of "Newton and Einstein, Lavoisier and Schrödinger,
Pasteur and Darwin." (6) And he believes that he knows why the scientific
community has not embraced intelligent design to explain cellular complexity:
"Why is the observation of design handled with intellectual gloves?
The dilemma is that while one side of the elephant is labeled intelligent
design, the other side might be labeled God." (7) So, according to
Behe, design is rejected by the scientific community for the most non-scientific
of reasons - its theological significance.

Behe has gone two centuries into the past to find the argument from design,
dusted it off, and invigorated it with the modern language of biochemistry.
But there are problems in this excursion. Not the least of these is the
fact that the argument from design has been answered, not once, but many
times by writers such as Dawkins, Gould, and even Darwin himself. The multiple
parts of complex, interlocking biological systems do not evolve as individual
parts, despite Behe's claim that they must. They evolve together, as systems
that are gradually expanded, enlarged, and adapted to new purposes. As Richard
Dawkins successfully argued in The Blind Watchmaker, natural selection
can act on these evolving systems at every step of their transformation.

As factual examples we could choose any of the systems whose evolution
is documented by the fossil record, a source apparently acceptable to Behe.
The three smallest bones in the human body, the malleus, incus, and stapes,
carry sound vibrations across the middle ear, from the membrane-like tympanum
(the eardrum) to the oval window. This five component system fits Behe's
test of irreducible complexity perfectly - if any one of its parts are taken
away or modified, hearing would be lost. This is the kind of system that
evolution supposedly cannot produce. Unfortunately for "intelligent
design," the fossil record elegantly and precisely documents exactly
how this system formed. During the evolution of mammals, bones that originally
formed the rear portion of the reptilian lower jaw were gradually pushed
backwards and reduced in size until they migrated into the middle ear, forming
the bony connections that carry vibrations into the inner ears of present-day
mammals. A system of perfectly-formed, interlocking components, specified
by multiple genes, was gradually refashioned and adapted for another purpose
altogether - something that this book claims to be impossible. As the well-informed
reader may know, creationist critics of this interpretation of fossils in
the reptile to mammal transition once charged that this could not have taken
place. What would happen, they joked, to the unfortunate reptile while he
was waiting for two of his jaw bones to migrate into the middle ear? The
poor creature could neither hear nor eat! As students of evolution may know,
A. W. Crompton of Harvard University brought this laughter to a deafening
halt when he unearthed a fossil with a double articulation of the jaw joint
- an adaptation that would allow the animal to both eat and hear during
the transition, enabling natural selection to favor each of the intermediate
stages.

Is there something special about biochemistry that prevents evolution
from doing exactly the same thing to a microscopic system composed of proteins?
Absolutely not. But evolution does make a testable prediction with
respect to such systems. That prediction is that the degree of similarity
in DNA sequences of organisms should correspond to their evolutionary histories.
And, as the author is all too well aware, that prediction has been borne
out a thousand times over.

Despite the close correspondence of gene sequence to fossil sequence,
Behe demands that evolutionary biologists should tell us exactly "how"
evolution can produce a complex biochemical system. This is a good strategic
choice on his part, because the systems he cites, being common to most eukaryotic
cells, are literally hundreds of millions of years old. And, being biochemical,
they leave no fossils. Once burned, twice shy, Behe may be hoping to avoid
the fate of his 1994 claim that there were no transitional fossils linking
the first fossil whales with their land-dwelling Mesonychid ancestors (8).
Less than a year after that prediction, the existence of not one, not two,
but three transitional species between whales and land-dwelling eocine
Mesonychids was confirmed. Nonetheless, it is quite possible to rise to
the occasion and answer his challenge in biochemical terms. In fact, Russell
Doolittle, whose investigations on the evolution of blood clotting are discussed
in this text, has done exactly this. Behe is at great pains to disqualify
this work, even though Doolittle has not only shown how such a complex system
might evolve, but has also produced comparative studies showing how
it probably did evolve.

In dismissing Doolittle's work, and in preempting any attempt to show
how evolution might produce a complex biochemical system, Behe scoffs at
the notion that a biochemical system adapted for one purpose might be adapted
by evolution for a totally different function, despite physiological examples
to the contrary in the fossil record. He dismisses, for example, the notion
that the parts of a cilium, including proteins like dynein and tubulin,
could have evolved by gene duplication even though similar forms of dynein
and tubulin are used for other purposes in the cell. Most cell biologists
will be unconvinced by his explanations of why the cilium could not have
been assembled from proteins originally used for other purposes - especially
since the cilium itself has been adapted for another purpose in one of the
very tissues that Behe uses as an example of design - the vertebrate photoreceptor
cell.

As the book draws to a conclusion, Behe attempts to develop the idea
of intelligent design into a testable, scientific hypothesis. This is a
lofty goal, but this is also where his argument collapses. Scientific ideas
must be formulated in terms that make them testable. Indeed, Darwin himself
proposed several ways in which his theory might be tested and disproved.
And one of these ways - the contention that organisms contain biochemical
parts that could not have been produced by Darwinian means - is the basis
of Behe's criticisms of evolution. Being a trained experimental scientist,
one would have expected that Behe would have seen the need to do likewise.
Unfortunately, he did not.

Let's suppose, for example, that a fellow scientist were to take Behe's
challenge to evolution seriously, and attempted to show how a specific biochemical
system composed of multiple parts could have evolved. A hypothesis for design,
formulated in genuinely scientific terms, must be disprovable, and this
is exactly the kind of evidence that might disprove it. Incredibly, Behe
has intentionally insulated "intelligent design" from this and
any other scientific test. How has he done this? In the penultimate chapter
of his text, he lists some of the driving forces associated with evolutionary
change, including natural selection, genetic drift, founder effects, gene
flow, meiotic drive, and transposition (9). Behe states that all of these
agents can effect change in biological systems, and admits that they may
account completely for at least some of the biochemical features of a living
cell. So, if our colleague were to show how these forces could have produced,
say, the bacterial flagellum, would he be entitled to say: "I have
disproved design?" Not at all, according to Behe. "The production
of some biological improvements by mutation and natural selection - by evolution
- is quite compatible with intelligent design theory." (10) In other
words, any evidence for the evolution of complexity is dismissed
in advance as being irrelevant to the problem of design. "Design"
exists only when and where evolution cannot explain it!

This sterile definition of design means that Behe is free to ignore any
conceivable evidence for the evolution of any biochemical system. Such an
idea, intentionally placed outside the realm of testability, is not science,
whatever the pretentions of its advocates.

If Behe's formulation of intelligent design as science is illogical,
his mechanism for how the work of the designer was inserted into living
systems is almost laughable. Remember that Behe accepts the validity of
the geological ages and the fossil record - an open-minded scientist can
hardly do otherwise - and yet he claims that the complex biochemical systems
he extols were fashioned by an intelligent agent. When did this agent go
to work, and when were the genes encoding them engineered? He has an answer
ready:

"Suppose that nearly four billion years ago the designer made
the first cell, already containing all of the irreducibly complex biochemical
systems discussed here and many others. (One can postulate that the designs
for systems that were to be used later, such as blood clotting, were present
but not "turned on." In present-day organisms plenty of genes
are turned off for a while, sometimes for generations, to be turned on
at a later time.)" (11)

This means that billions of years ago a humble prokaryote was packed
with genes that would be turned off for hundreds of millions of years before
they produced the eukaryotic cilium, and genes for blood clotting proteins
that would pass more than a billion inactive years in genetic "cold
storage." And what happens during those billions of years? As any student
of genetics will tell you, because those genes are not expressed, natural
selection cannot weed out genetic mistakes. This means that mutations will
accumulate in these genes at breathtaking rates, rendering then hopelessly
changed and inoperative hundreds of millions of years before Behe says that
they will be needed.

Contrary to Behe's claims, the evidence of evolution in the fossil record
is not irrelevant to his argument. It has forced him, for the sake of consistency,
to cobble his acceptance of the earth's well-documented natural history
together with the doctrine of intelligent design. The result is an absolutely
hopeless genetic fantasy of "pre-formed" genes waiting for the
organisms that might need them to gradually appear. This absurdity is the
unavoidable result of trying to make "design" conform to that
troublesome fossil record. The very same fossil record that provides the
primary evidence for evolution.

However serious its scientific flaws, this interesting and colorful book
is sure to attract attention. Michael Behe would like us to believe that
he has discovered a new biological principle. But the real news in Darwin's
Black Box is that a contemporary scientist has dipped back into the
past and wrapped the remains of the Argument from Design in a shiny cloth
of biochemistry. In this new clothing, the old idea may surprise a few unsuspecting
readers who have not thought long or seriously about the mechanisms of evolution.
They may be entertained by Behe's energy, and sustained by his enthusiasm.
But ultimately, the careful reader will recognize this book for what it
truly is - an argument against evolution that concedes nearly all the contested
ground to Darwin's edifice, and then ends up teetering on little more than
rhetoric and personal skepticism